1. Field of the Invention
This invention relates to laser systems and, more particularly, to electronic controllers for controlling and monitoring operations of a tunable laser, such as an external cavity diode laser.
2. Description of the Related Art
Tunable external cavity diode lasers (ECDLs) are widely used in lightwave test-and-measurement equipment and are becoming recognized as essential components for the rapidly expanding fields of wavelength division multiplexed (WDM) optical voice and data communications. The many applications within these fields represent many different sets of performance specifications. However, the following requirements are typical: small size of the optomechanical assembly and control system;, servo control of the wavelength; and controllable frequency modulation (FM) at audio rates (e.g., 100 Hz to 30 kHz) in order to broaden the linewidth.
To achieve desired control over the operation of external cavity diode lasers, electronic controllers are typically provided that implement various functionality. This functionality may include a current source for providing current to the laser, locked wavelength tuning functionality, a modulation source, and various other functionality to precisely control and monitor operation of the tunable laser. It is typically desirable that the electronic controller allow for versatile control of the tunable laser with reasonable efficiency and a relatively small form factor. It is also typically desirable that electrical noise within the system and its impact upon various measurement functions be minimized.